ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The almost lossless transfer of energy and electronic charge along quasi-one-dimensional molecular substances such as peptide chains (H — N — C = O)n found an explanation in a model proposed by Davydov. The Davydov model is based on the dipole - dipole interactions between neighboring peptide groups and on the fact that the internal C=O vibrations are coupled to the elastic deformations of the chain. The Davydov Hamiltonian is written in the position-space representation and, on making a continuum transformation, leads to a nonlinear Schrödinger equation whose solutions are solitons. A Davydov soliton is a coupled pair of an exciton and a lattice deformation. In this paper, the Davydov Hamiltonian is transformed to the reciprocal lattice and its equivalent, second-quantized Hamiltonian is investigated. Some important observations are made about the coupling constants, their dispersion relations, and the equation of motion for the ladder operators. Our procedure is free of semiclassical approximations but, instead, assumes the onset of Bose condensation. The resultant nonlinear Schrödinger equation is similar to that of Davydov, but a more complete set of solutions is found.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560290312
